1. Field of the Invention
The embodiments of the invention comprise a self-aligned super stressed p-type field effect transistor (PFET).
2. Description of the Related Art
Strain engineering has become the main method to drive device performance in recent complementary metal oxide semiconductor (CMOS) technology generations. Carbon-doped silicon (Si:C), which has a smaller lattice constant than silicon, can insert compressive strain in the PFET channel when a layer of carbon-doped silicon is put directly under the PFET channel regain. On the other hand, silicon germanium (SiGe) which has a larger lattice constant than silicon also can insert compressive strain in the PFET channel when it is epitaxially grown in source and drain regions. Moreover, carbon-doped silicon can help reduce B diffusion and improve the epitaxial quality of silicon germanium.